Unio plicata Say, 1817
‘LeSueur’ Say, 1817. Nich. Encyc. 2: [12].
‘LeSueur’ Say, 1819. Nich. Encyc. 4: [17].
Say, 1858. [in] Binney, Compl. Writings T. Say: 50.
Type(s): NEOTYPE SMF_4305, Ohio, U.S.A.

Quadrula (sec. Crenodonta) plicata — Simpson (1900), Simpson (1914)
Unio (s.s.) plicatus — Call (1900)
Crenodonta plicata — Ortmann (1912)
— de Gregorio (1914)
Amblema plicata — Ortmann & Walker (1922), Modell (1942), Heard & Guckert (1970), Clarke (1973), Burch (1975), ... Matos et al. (2024), Dai et al. (2025), Freeman et al. (2025), Chen et al. (2025), FMCS (2025)
Amblema (s.s.) plicata — Frierson (1927), Haas (1930)
Crenodonta peruviana peruviana — Murray & Leonard (1962)
Amblema plicata plicata — Haas (1969), Turgeon et al. (1988), Williams et al. (1993), Watters et al. (2009)
Amblema plicatus — Mackie et al. (1980)
Amblema p. plicata — Hoke (2005)

Unio peruviana Lamarck, 1819
Bruguière, 1797. Encycl. Méth. 2: pl. 248, fig. 7 [as Unio sp.].
Lamarck, 1819. Hist. Natur. Anim. sans Vert. 6: 71, sp. 4.

Quadrula (sec. Crenodonta) plicata — Simpson (1900), Simpson (1914)
Amblema peruviana — Utterback (1915), Ortmann & Walker (1922), F.C. Baker (1928)
Amblema costata — Ortmann (1925)
Amblema (s.s.) plicata — Frierson (1927)
Crenodonta peruviana peruviana — Murray & Leonard (1962)
Amblema plicata plicata — Haas (1969), Watters et al. (2009)
Amblema plicata — Burch (1975), Mathiak (1979), R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)

Unio rariplicata Lamarck, 1819
Lamarck, 1819. Hist. Natur. Anim. sans Vert. 6: 71, sp. 5.
Type(s): HOLOTYPE MNHN_MPL_0037, Habite la rivière de l’Ohio. Michaud.

Quadrula (sec. Crenodonta) plicata — Simpson (1900), Simpson (1914)
Amblema rariplicata — Utterback (1915), F.C. Baker (1928)
Amblema plicata — Ortmann & Walker (1922), R.I. Johnson (1969), Burch (1975), R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)
Amblema (s.s.) plicata — Frierson (1927)
Amblema plicata plicata — Haas (1969), Watters et al. (2009)

Amblema costata Rafinesque, 1820
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 315, pl. 82, figs. 13-14 [also as ‘Unio costata’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 58.
Type(s): LECTOTYPE ANSP_20246, small creeks, Kentucky.

— Simpson (1900), Simpson (1914)
Amblema (plicata) costata — Utterback (1915)
Quadrula costata — Vanatta (1915)
Amblema plicata costata — Ortmann (1918), Haas (1969)
Amblema costata — Ortmann & Walker (1922), Ortmann (1924), Ortmann (1925), F.C. Baker (1928), Thiele (1934), MacNeil (1935), ITIS (2012)
Amblema (s.s.) plicata-costata — Frierson (1927)
Crenodonta peruviana costata — Murray & Leonard (1962)
Amblema (s.s.) plicata costata — Haas (1969)
Amblema plicata — Heard & Guckert (1970), Clarke (1973), Burch (1975), R.I. Johnson (1980), Oesch (1984), ... Parmalee & Bogan (1998), Graf & Cummings (2007), Williams et al. (2008), He & Zhuang (2013), Graf & Cummings (2021)
Amblema plicata plicata — Watters et al. (2009)

Unio undulatus Barnes, 1823
Barnes, 1823. Amer. J. Sci. 6 (1-2): 120, pl. 2, fig. 2a-b.

Quadrula (sec. Crenodonta) undulata — Simpson (1900), Simpson (1914)
Unio (s.s.) undulatus — Call (1900)
Quadrula undulata — Ortmann (1909), Ortmann (1909), Ortmann (1909), Ortmann (1910)
Crenodonta undulata — Ortmann (1912)
Unio undulatus — de Gregorio (1914)
Amblema (plicata) costata — Utterback (1915)
Quadrula costata — Vanatta (1915)
Megalonaias gigantea — Ortmann & Walker (1922), F.C. Baker (1928), Burch (1975)
Amblema costata — Ortmann & Walker (1922)
Amblema (Megalonaias) gigantea — Frierson (1927)
Crenodonta peruviana costata — Murray & Leonard (1962)
Amblema plicata — R.I. Johnson (1980), Oesch (1984), Vidrine (1993), Strayer & Jirka (1997), Williams et al. (2008), He & Zhuang (2013)
Megalonaias nervosa — Howells et al. (1996), Williams et al. (2008), Watters et al. (2009)

Unio costatus Conrad, 1836
‘Rafinesque’ of Authors.
Conrad, 1836. Monogr. Fam. Unionidae 1(2): pl. 17, fig. 7.
Reeve, 1864. Conch. Icon. 16: pl. 4, sp. 16.

Quadrula (sec. Crenodonta) undulata — Simpson (1900), Simpson (1914)
Amblema plicata — He & Zhuang (2013)

Unio perplicatus Conrad, 1841
Conrad, 1841. Proc. Acad. Nat. Sci. 1: 19.
Conrad, 1850. Jour. Acad. Nat. Sci. 1: 276, pl. 38, fig. 2.
Conrad, 1853. Proc. Acad. Nat. Sci. 6: 261 [as ‘Plectomerus perplicatus’].
Type(s): HOLOTYPE ANSP_129919, Jackson, Miss.

Quadrula (sec. Crenodonta) perplicata — Simpson (1900), Simpson (1914)
Crenodonta perplicata — Ortmann (1912), Ortmann (1914)
Amblema perplicata — Utterback (1915), Davis & Fuller (1981), Lydeard et al. (1996), Krebs et al. (2003)
Amblema perplicatus — Ortmann (1923)
Amblema costata — Ortmann (1924)
Amblema (s.s.) plicata-perplicata — Frierson (1927)
Amblema plicata costata — Haas (1969)
Amblema plicata — Burch (1975), R.I. Johnson (1980), Vidrine (1993), Howells et al. (1996), Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013), Patterson et al. (2021)
Amblema plicata perplicata — Turgeon et al. (1988), Williams et al. (1993), Watters et al. (2009)
Amblema elliottii — Mulvey et al. (1997)

Unio atrocostatus Lea, 1845
Lea, 1845. Proc. Amer. Phil. Soc. 4: 163.
Lea, 1848. Trans. Amer. Phil. Soc. 10 [O. 4]: 70 [44], pl. 2, fig. 5 [as ‘atro-costatus’].

Quadrula (sec. Crenodonta) perplicata — Simpson (1900), Simpson (1914)
— de Gregorio (1914)
Amblema (s.s.) plicata-perplicata — Frierson (1927)
Amblema plicata costata — Haas (1969)
Amblema plicata — Williams et al. (2008), He & Zhuang (2013)
Megalonaias nervosa — Watters et al. (2009)

Unio hippopoeus Lea, 1845
Lea, 1845. Proc. Amer. Phil. Soc. 4: 163 [as ‘hippopœus’].
Lea, 1848. Trans. Amer. Phil. Soc. 10 [O. 4]: 67 [41], pl. 1, fig. 1 [as ‘hippopœus’].
Type(s): HOLOTYPE USNM_84096, L. Erie.

Quadrula (sec. Crenodonta) plicata var. hippopæa [sic] — Simpson (1900), Simpson (1914)
Quadrula hippopæa [sic] — Ortmann (1909)
Quadrula undulata hippopæa [sic] — Ortmann (1909)
Amblema (s.s.) plicata-hippopaea [sic] — Frierson (1927)
Amblema plicata costata — Haas (1969)
Amblema plicata — Clarke (1973), Burch (1975), Strayer & Jirka (1997), Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)
Amblema plicata plicata — Watters et al. (2009)

Unio latecostatus Lea, 1845
Lea, 1845. Proc. Amer. Phil. Soc. 4: 163.
Lea, 1848. Trans. Amer. Phil. Soc. 10 [O. 4]: 68 [42], pl. 1, fig. 2.
Type(s): POSSIBLE SYNTYPE ANSP_127444, Ala. River, Selma, Alabama.

Quadrula (sec. Crenodonta) undulata var. latecostata — Simpson (1900), Simpson (1914)
— de Gregorio (1914)
Amblema (s.s.) plicata-costata — Frierson (1927)
Amblema plicata — Howells et al. (1996), Williams et al. (2008), He & Zhuang (2013)

Unio hippopaeus Lea, 1852
‘Lea’ of Authors.
Lea, 1852. Synopsis Fam. Naiades: 21 [as ‘hippopæus’].
Conrad, 1853. Proc. Acad. Nat. Sci. 6: 261 [as ‘hippopæus’].
Adams & Adams, 1857. Gen. Rec. Moll. 2(31-32): 497 [as ‘hippopæus’].
Reeve, 1864. Conch. Icon. 16: pl. 11, sp. 40 [as ‘hippopæus’].
Lea, 1870. Synopsis Fam. Naiades: 31 [as ‘hippopæus’].
B.H. Wright, 1888. Check List N. Amer. Unionidae etc.: [3], [as ‘hippopæus’].
Simpson, 1900. Proc. U.S. Nat. Mus. 22: 767 [as ‘hippopæa’].
Ortmann, 1909. Nautilus 22(10): 101 [as ‘Q. hippopæa’].
Ortmann, 1909. Ann. Carnegie Mus. 5: 203 [as ‘Quadrula undulata hippopæa’].
Simpson, 1914. Descr. Cat. Naiades: 816 [as ‘hippopæa’].
Frierson, 1927. Check List N. Amer. Naiades: 61.
Haas, 1969. Das Tierreich 88: 287.
Clarke, 1973. Malacologia 13(1-2): 35.
Burch, 1975. Freshw. Unio. North Amer.: 165.
Strayer & Jirka, 1997. Pearly Mussels NY (26): 98.
He & Zhuang, 2013. Freshwater Bivalves China: 27.

Amblema plicata plicata — Watters et al. (2009)

Unio pearlensis Conrad, 1855
Conrad, 1855. Proc. Acad. Nat. Sci. 7: 256.
Type(s): LECTOTYPE ANSP_129918, Pearl River, Miss.

Quadrula (sec. Crenodonta) perplicata — Simpson (1900), Simpson (1914)
Amblema (s.s.) plicata-perplicata — Frierson (1927)
Amblema plicata costata — Haas (1969)
Amblema plicata — Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)
Amblema plicata plicata — Watters et al. (2009)

Unio plicatus Küster, 1856
‘Say’ of Authors.
Küster, 1856. Conchyl. Cab. 9(2): 137, pl. 40, fig. 3.
Chenu, 1859. Manuel Conchyl. 2: 143, pl. 706.

Quadrula (sec. Crenodonta) undulata — Simpson (1900), Simpson (1914)
Strophitus undulatus — Vidrine (1993)
Amblema plicata — He & Zhuang (2013)

Unio laticostatus Adams & Adams, 1857
‘Lea’ of Authors.
Adams & Adams, 1857. Gen. Rec. Moll. 2(31-32): 497.
Lea, 1870. Synopsis Fam. Naiades: 31.
Singley, 1893. Geol. Surv. Texas (1892): 317.

Quadrula (sec. Crenodonta) undulata var. latecostata — Simpson (1900), Simpson (1914)

Unio perlensis Reeve, 1864
‘Conrad’ of Authors.
Reeve, 1864. Conch. Icon. 16: pl. 11, sp. 42.
Paetel, 1890. Cat. Conch.-Samml. 3: 163.

Quadrula (sec. Crenodonta) perplicata — Simpson (1900), Simpson (1914)
Amblema (s.s.) plicata-perplicata — Frierson (1927)
Amblema plicata — Parmalee & Bogan (1998)

Unio brazosensis Lea, 1868
Lea, 1868. Proc. Acad. Nat. Sci. 20: 144.
Lea, 1868. Jour. Acad. Nat. Sci. 6 [O. 12]: 309 [69], pl. 48, fig. 122.
Type(s): FIGURED SYNTYPE USNM_84110, Brazos River, Tex.

Quadrula (sec. Crenodonta) perplicata — Simpson (1900), Simpson (1914)
Amblema (s.s.) plicata-perplicata — Frierson (1927)
Amblema plicata costata — Haas (1969)
Amblema plicata — Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)
Amblema plicata plicata — Watters et al. (2009)

Unio lincecumii Lea, 1868
Lea, 1868. Proc. Acad. Nat. Sci. 20: 144.
Lea, 1868. Jour. Acad. Nat. Sci. 6 [O. 12]: 312 [72], pl. 49, fig. 125.
Type(s): FIGURED SYNTYPE USNM_84112, Dallas Co., Texas.

Quadrula (sec. Crenodonta) perplicata — Simpson (1900), Simpson (1914)
— de Gregorio (1914)
Amblema (s.s.) plicata-perplicata — Frierson (1927)
Amblema plicata costata — Haas (1969)
Amblema plicata — Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)
Amblema plicata plicata — Watters et al. (2009)

Unio pauciplicatus Lea, 1872
Lea, 1872. Proc. Acad. Nat. Sci. 24: 156.
Lea, 1874. Jour. Acad. Nat. Sci. 8 [O. 13]: 29 [33], pl. 9, fig. 26.
Type(s): FIGURED SYNTYPE USNM_84111, Austin, Texas.

Quadrula (sec. Crenodonta) perplicata — Simpson (1900), Simpson (1914)
Amblema (s.s.) plicata-perplicata — Frierson (1927)
Amblema plicata costata — Haas (1969)
Amblema plicata — Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)
Amblema plicata plicata — Watters et al. (2009)

Unio quintardii Cragin, 1887
Cragin, 1887. Bull. Washburn Coll. 2: 6.
Type(s): HOLOTYPE ANSP_63304, Sac & Fox Reservation, Oklahoma.

Quadrula (sec. Crenodonta) perplicata var. quintardii — Simpson (1900), Simpson (1914)
Amblema perplicata quintardi — Utterback (1915)
Amblema (s.s.) plicata-quintardi — Frierson (1927)
Amblema plicata costata — Haas (1969)
Amblema plicata — R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)
Amblema plicata plicata — Watters et al. (2009)

Unio pilsbryi Marsh, 1891
Marsh, 1891. Nautilus 5(1): 1.
Pilsbry, 1892. Proc. Acad. Nat. Sci. 44: 131, pl. 8, figs. 7-8.
Pilsbry, 1893. Nautilus 7(1): pl. 1, figs. 7-8.
Type(s): HOLOTYPE ANSP_41589, Little Red River, Ark.

Quadrula (sec. Crenodonta) undulata var. pilsbryi — Simpson (1900), Simpson (1914)
Amblema perplicata quintardi — Utterback (1915)
Amblema (s.s.) plicata-pilsbryi — Frierson (1927)
Amblema plicata costata — Haas (1969)
Amblema plicata — R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)
Amblema plicata plicata — Watters et al. (2009)

Cokeria southalli Marshall, 1916
Marshall, 1916. Nautilus 29: 133.
Type(s): HOLOTYPE USNM_215130, James R., Huron, South Dakota.

Amblema (s.s.) plicata-southalli — Frierson (1927)
Amblema costata — Thiele (1934)
Amblema plicata costata — Haas (1969)
Cokeria southalli — Haas (1969)
Amblema plicata — R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), He & Zhuang (2013)
Amblema plicata plicata — Watters et al. (2009)

Unio multiplicata of Authors, unknown year
Desh. of Authors.

Unio undulatus of Authors, unknown year
Desh. of Authors.

Unio crassus Barnes, 1823
‘Say’ Barnes, 1823. Amer. J. Sci. 6 (1-2): 118, figs. 1a-b.

Quadrula (sec. Crenodonta) plicata — Simpson (1900), Simpson (1914)
Quadrula (Fusconia [sic]) subrotunda — Frierson (1927)
Amblema plicata plicata — Watters et al. (2009)
Amblema plicata — He & Zhuang (2013)

Unio gigantea Lea, 1838
‘Barnes’ Lea, 1838. Trans. Amer. Phil. Soc. 6 [O. 2]: 31, 35.

Quadrula (sec. Crenodonta) plicata — Simpson (1900), Simpson (1914)
Amblema plicata — Parmalee & Bogan (1998), He & Zhuang (2013)
Amblema plicata plicata — Watters et al. (2009)

Unio undulatus Hanley, 1843
‘Barnes’ Hanley, 1843. Illustr. Descr. Cat. Rec. Bivalve Shells: 175, pl. 20, fig. 26.

Quadrula (sec. Crenodonta) undulata — Simpson (1900), Simpson (1914)
Amblema costata — Ortmann (1924), F.C. Baker (1928)
Amblema plicata — Parmalee & Bogan (1998), He & Zhuang (2013)

Margaron (Unio) laticostasus Lea, 1852
Lea, 1852. Synopsis Fam. Naiades: 21.

Unio heros Küster, 1855
‘Say’ Küster, 1855. Conchyl. Cab. 9(2): 136, pl. 40, figs. 1-2.

Quadrula (sec. Crenodonta) plicata — Simpson (1900), Simpson (1914)
Amblema (s.s.) plicata — Frierson (1927)
Amblema plicata plicata — Haas (1969), Watters et al. (2009)
Amblema plicata — Parmalee & Bogan (1998)

Unio perplicatus Reeve, 1864
‘Conrad, Anthony, MS.’ Reeve, 1864. Conch. Icon. 16: pl. 9, sp. 35; errata [changed to ‘U. atrocostatus’].

Unio (s.s.) multiplicatus — Call (1900)
Quadrula (sec. Crenodonta) perplicata — Simpson (1900)

Unio guintardii B.H. Wright, 1888
‘Cragin’ B.H. Wright, 1888. Check List N. Amer. Unionidae etc.: [3].

Unio lincecurei Paetel, 1890
‘Lea’ Paetel, 1890. Cat. Conch.-Samml. 3: 157.

Quadrula (sec. Crenodonta) perplicata — Simpson (1900), Simpson (1914)
Amblema plicata plicata — Watters et al. (2009)